A great deal of research is currently underway to develop treatments and cures for viral infections in humans and in animals. Notably the incidence of acquired immune deficiency syndrome (AIDS) and AIDS related complex (ARC) in humans is increasing at an alarming rate. The five year survival rate for those with AIDS is dispiriting and AIDS patients, whose immune systems have been seriously impaired by the infection, suffer from numerous opportunistic infections including Kaposi's sarcoma and Pneumocystis carninii pneumonia. No cure is known and current treatments are largely without adequate proof of efficacy and have numerous untoward side effects. Fear of the disease has resulted in social ostracism of and discrimination against those having or suspected of having the disease.
Retroviruses are a class of ribonucleic acid (RNA) viruses that replicate by using reverse transcriptase to form a strand of complementary DNA (cDNA) from which a double stranded, proviral DNA is produced. This proviral DNA is then randomly incorporated into the chromosomal DNA of the host cell. Further transcription and translation of the integrated viral genome DNA results in viral replication through the synthesis of virus specific RNA and proteins.
Many of the known retroviruses are oncogenic or tumor causing. Indeed the first two human retroviruses discovered, denoted human T-cell leukemia virus I and II or HTLV-I and II, were found to cause rare leukemias in humans after infection of T-lymphocytes. The third such human virus to be discovered, HTLV-III, now referred to as HIV, was found to cause cell death after infection of T-lymphocytes and has been identified as the causative agent of acquired immune deficiency syndrome (AIDS) and AIDS related complex (ARC).
Among the substances previously shown to have activity against HIV and other retroviruses are such diverse compounds as azidothymidine, castanospermine, and heparin.
The applicants have now discovered that certain substituted furan ketones, more specifically furan ketones substituted at the 5-position of the furan ring by phenoxyalkyl and naphthylenyloxyalkyl moieties bonded to the furan ring either directly, through an ether or thioether bridge, or through an oxymethyl or thiomethyl bridge, are useful in the treatment of various retroviral infections including in the treatment of AIDS and ARC resulting from infection by HIV or other retroviruses.